1. Field of the Invention
The invention in general relates to spectral imaging systems and more particularly to testing apparatus for testing a hyperspectral imaging system under various atmospheric or other environmental conditions.
2. Description of Related Art
A popular form of imaging system is the hyperspectral imaging system whereby a region of interest is examined utilizing a plurality of filters which allow respective wavelengths of radiation to sequentially or simultaneously impinge upon a detector array. This technique allows identification of certain desired aspects of the region.
For example, such systems may be used by the military to detect various predetermined targets. The systems also find use in the commercial and environmental fields for determining, by way of example, certain weeds, vegetation, blight, mineral detection, hazardous waste, and soil erosion. The foregoing is but a small sample of the use to which these systems are put.
Generally the signature of a desired feature is known by prior data acquisition before the system is utilized in the field, such that only specific wavelength filters need be employed for the detection process. The response of the system is tested in the laboratory prior to deployment.
However, under actual use in the field, various atmospheric conditions may occur such that one or more wavelengths radiated from the region under investigation, and used in the detection process, will be absorbed, either partially or totally. In addition, certain targets may emit atmospheric radiation such as hot exhaust gases. Therefore to have a viable hyperspectral imaging system, it is necessary to know, a priori, the response of the system under conditions where certain useful wavelengths may be absorbed or generated. The present invention provides a solution to this problem.